Check out some of the papers that were recently published by DMCBH members:
Naznin Virji-Babul: Changes in EEG Microstate Dynamics and Cognition Post-Chemotherapy in People With Breast Cancer
Journal: Brain and Behaviour
Although it is known that chemotherapy for breast cancer can result in cognitive changes, it is unclear how brain dynamics of large-scale neural networks change. Using data from the Aerobic exercise and CogniTIVe functioning in women with breAsT cancEr (ACTIVATE) trial, researchers conducted exploratory analyses to examine measures of cognition and resting state electroencephalography (EEG) data of women with breast cancer before and after chemotherapy treatment. Following chemotherapy, there was a significant decrease in measures of cognitive function. Overall, EEG analysis found longer microstate durations which were less evenly distributed. The mean duration of microstate D, which is known for its involvement in attention and executive function, was significantly increased after chemotherapy. This exploratory study provided new evidence showing that changes occur in large-scale brain dynamics related to the cognitive effects of chemotherapy.
Mypinder Sekhon: The dynamic pathophysiology of post cardiac arrest brain injury: “time is brain”
Journal: Current opinion in clinical care
Post-cardiac arrest brain injury (PCABI) is the primary cause of mortality and adverse outcomes in patients who survive cardiac arrest. PCABI has a diverse and dynamic pathophysiology, characterized broadly by mechanisms associated with impaired blood flow to the brain. However, interventions that improve cerebral oxygen delivery have not demonstrated improved outcomes. PCABI pathophysiology must be viewed in a time dependent manner and interventions aimed at restoring cerebral oxygen delivery are likely to only work if applied immediately.
Journal: BMJ (Clinical research edition)
This study predicted the global, regional, and national prevalence of Parkinson’s disease (PD) by age, sex, year and sociodemographic index to 2050. Using data from the Global burden of disease study (2021), researchers projected that 25.2 million people could be living with PD worldwide in 2050, representing a 112% increase from 2021. Population aging was predicted to be the primary contributor to this substantial growth, followed by population growth and changes in prevalence. The prevalence of PD was forecasted to be 267 cases per 100,000 in 2050, a significant increase of 76% from 2021. By 2050, it is predicted that PD will become a greater public health challenge, representing a need for promoting health research, informing policy decisions and allocating resources.
Kiran Soma: Maternal sucrose consumption alters steroid levels in the mother, placenta and fetus
Journal: Journal of Endocrinology
Sucrose (table sugar) intake is high in modern diets, taking up an estimated 25% of calories a day. While it is clear that maternal diet has long-term effects on offspring brain and behaviour, the consequences of high sucrose consumption are lesser known. In rats, a maternal high-sucrose diet (HSD) with 26% sucrose alters maternal metabolism and brain, also altering adult offspring hormones and behaviour in a sex-specific manner. Maternal sucrose increases stress hormone levels in adult female offspring and increases motivation for sugar rewards in males. The present study used liquid chromatography-tandem mass spectrometry to examine how HSD affected steroids in the mother, placenta and fetus. The study found dramatic and widespread changes which might mediate the long-term effects of maternal sucrose consumption on adult offspring hormones and behaviour.
Jason Barton: The lateralization of reading
Journal: Handbook of clinical neurology
Reports from as early as the 1890s described reading disorders arising from left hemisphere damage. Further work has confirmed a strong dependence of reading on the left ventral occipitotemporal cortex, though the right hemisphere may also have reading capacity. This leftward bias is reflected in reading acquisition and developmental dyslexia. This review explored the left ventral occipitotemporal cortex and its involvement in diverse types of reading.
Stan Floresco: Valence-dependent contribution by the basolateral amygdala to active but not inhibitory avoidance and reward-seeking
Journal: Behavioural Brain Research
This study explores how the basolateral amygdala (BLA), a brain region involved in emotion and decision-making, helps animals decide when to take action or hold back to avoid danger or seek rewards. The present study examined BLA involvement in different avoidance strategies in male and female rats which were trained on different lever-press avoidance and reward-seeking tasks. Researchers trained rats to press a lever to either prevent a mild shock or receive a treat, sometimes using different sounds to signal when to act or stay still. When the BLA was temporarily inactivated, the rats had trouble taking action to avoid shocks or get rewards but were slightly better at staying still when needed. However, when only one cue was used—meaning there was no need to choose between different signals—the BLA was only important for avoiding danger, not for seeking rewards. These findings suggest that the BLA plays a key role in guiding behavior when choices are complex but may be less involved when decisions are more straightforward.
Terry Snutch: Maturational Stage Dependent Contributions of the Cav3.2 T-type Calcium Channel to Dentate Gyrus Granule Cell Excitability
Journal: eNeuro
This study examines how Cav3.2 T-type calcium channels influence the electrical activity of granule cells (GCs) in the dentate gyrus (DG), a part of the brain important for learning, memory, and epilepsy. The DG continuously produces new neurons, which mature over time and change how they interact with brain circuits. Researchers studied juvenile mice lacking Cav3.2 channels (KO mice) to see how this affected GC excitability at different stages of development. They found that in immature neurons, losing Cav3.2 reduced the proportion of cells that fired low threshold calcium spikes, while in more mature neurons, it actually increased their firing rates. These findings suggest that Cav3.2 channels play different roles as neurons develop, potentially affecting memory formation and epilepsy risk.
Stan Floresco: Medial orbitofrontal, prefrontal and amygdalar circuits support dissociable component processes of risk/reward decision making
Journal: The Journal of Neuroscience
This study explores how different brain circuits help animals make decisions when faced with uncertain rewards. The medial orbitofrontal cortex (mOFC) plays a key role in using past experiences to predict future outcomes, but how it interacts with other brain regions to do this remains unclear. Researchers trained rats to choose between a guaranteed small reward or a larger but uncertain reward, with the odds changing over time. By temporarily silencing specific brain pathways, they found that blocking mOFC signals to the basolateral amygdala (BLA) disrupted the rats’ ability to adjust their choices based on changing reward probabilities. However, blocking signals from the BLA to the mOFC had no effect. In contrast, disrupting communication between the mOFC and another brain region, the prelimbic cortex (PL), led to more random decision-making, suggesting that this pathway helps process past wins and losses. These findings highlight how different brain circuits contribute to decision-making under uncertainty and may provide insight into how these processes go wrong in psychiatric conditions.
Helen Tremlett: Characterizing the diversity of the multiple sclerosis population in Canada: A scoping review
Journal: Multiple Sclerosis Journal – Experimental, Translational and Clinical
This review examined the diversity of people with multiple sclerosis (MS) in Canadian research, highlighting gaps in representation. Analyzing 259 studies from 2010 to early 2024, researchers found that most focused on disease-modifying treatments (24.3%) and healthcare access (20.9%), with participant recruitment primarily through MS clinics and MS Canada. While age (92.7%) and sex (86.9%) were frequently reported, less than 10% of studies included race or ethnicity, and no studies reported religion, sexual orientation, or language. This limited representation suggests that existing research does not fully capture the diverse experiences of people with MS in Canada, potentially impacting health equity. To address this, future studies should improve demographic reporting and actively recruit more diverse participants.
Read the blog post here.
Shernaz Bamji: The X-Linked Intellectual Disability Gene, ZDHHC9, Is Important for Oligodendrocyte Subtype Determination and Myelination
Journal: Glia
Loss-of-function mutations in the enzyme ZDHHC9 are linked to X-linked intellectual disability (XLID) and are associated with reduced corpus callosum volume and impaired white matter integrity. This study found that deleting Zdhhc9 in mice altered the balance of mature oligodendrocyte subtypes in the corpus callosum without affecting overall oligodendrocyte numbers. Specifically, there was an increase in MOL5/6 cells, which are associated with cell adhesion and synapses, and a decrease in MOL2/3 cells, which play a role in myelination. These changes correlated with a reduction in myelinated axon density and disruptions in myelin compaction. Further RNA sequencing and proteomic analysis revealed decreased expression of genes and proteins crucial for lipid metabolism, cholesterol synthesis, and myelin structure. These findings highlight an important role for ZDHHC9 in oligodendrocyte subtype regulation and myelin formation, shedding light on the white matter deficits seen in individuals with ZDHHC9 mutations.
Helen Tremlett: Scoping review of the availability and uptake of disease modifying therapies in children and adolescents with multiple sclerosis
Journal: Expert Review of Clinical Pharmacology
Pediatric-onset multiple sclerosis (MS), which affects about 10% of individuals with MS, presents unique challenges in accessing disease-modifying therapies (DMTs). Barriers include a lack of pediatric-specific randomized controlled trials (RCTs), which are often required for regulatory approval, leading to cost and coverage difficulties. This scoping review examined real-world DMT use in pediatric MS to identify potential access barriers. Analyzing 88 observational studies published between 1993 and 2024, the review included data on 21,591 patients, of whom 68.7% received DMTs. Most studies originated from Europe (53.4%), North America (22.7%), and the Middle East (10%), revealing regional variations in DMT uptake. However, only a small portion (14.8%) of studies provided information on DMT funding sources. The findings highlight low DMT use among pediatric-MS patients and a lack of data on specific barriers to access, emphasizing the need for further research to understand and address regional disparities.
William Panenka, Noah Silverberg, Donna Lang, Cheryl Wellington, Jon Stoessl, Vesna Sossi, Thalia Field: Diffusion tensor imaging after COVID-19 infection: A systematic review
Journal: NeuroImage
This systematic review evaluated advanced neuroimaging studies on diffusion MRI (dMRI) abnormalities following COVID-19, focusing on changes in brain structure beyond the acute phase of illness. A literature search on PubMed, Embase, and Scopus identified 1709 records, with 11 studies meeting inclusion criteria. Most studies involved hospitalized COVID-19 patients who underwent brain MRI 2 to 6 months post-infection. The majority reported lower fractional anisotropy and higher mean diffusivity in COVID-19 patients, suggesting white matter integrity disruptions. However, findings varied, with one study showing increased fractional anisotropy. More severe acute illness correlated with greater structural abnormalities, while longer intervals between infection and MRI were linked to fewer differences. The heterogeneity of results may stem from illness severity and imaging timing, underscoring the need for future research on the effects of different SARS-CoV-2 variants on brain structure.
Howard Feldman, Julie Robillard, Haakon Nygaard, Teresa Liu-Ambrose: Brain health PRO/Santé cerveau PRO: The development of a web-based program for dementia literacy and risk factor reduction
Journal: The Journal of Prevention of Alzheimer’s disease
This study aimed to develop an evidence-based online educational program focused on dementia risk and protective factors, with the goal of increasing brain health literacy and empowering participants to engage in activities that support brain health. The Brain Health PRO/Santé Cerveau PRO program is a web-based, 45-week educational tool that covers seven modifiable dementia risk factors: physical activity, nutrition, cognitive stimulation, sleep, social and psychological health, vascular health, and vision/hearing. The program, available in both French and English, personalizes the content through individualized risk profiles and offers feedback on lifestyle changes. In a pilot study with 20 community-dwelling older adults in Canada, the program was delivered remotely. The results showed excellent usability (80.4/100) and acceptance (93.5/120) among participants, demonstrating that the program effectively balances scientific content with the needs and abilities of older adults. The development process used intervention mapping and co-construction approaches to ensure the program met the target audience’s needs. This pilot suggests that such online programs may support dementia prevention by engaging participants in positive brain health behaviors.
William Panenka, Noah Silverberg, Donna Lang, Cheryl Wellington, Jon Stoessl, Vesna Sossi, Thalia Field: Quantitative brain volume differences between COVID-19 patients and non-COVID-19 volunteers: A systematic review
Journal: NeuroImage
This systematic review aimed to evaluate the chronic effects of COVID-19 on brain structure, focusing on volumetric differences between COVID-19 patients and healthy volunteers more than 6 weeks after infection. While most studies reported smaller grey matter volumes in COVID-19 patients, three studies showed the opposite, with larger grey matter volumes in the COVID-19 groups. The review found that COVID-19 patients with more severe illness, including those admitted to the hospital or ICU, were more likely to exhibit reduced grey matter volumes compared to healthy volunteers, whereas studies on patients who recovered at home showed less pronounced changes. These findings suggest that the severity of COVID-19 illness may contribute to the inconsistencies in reported brain volume differences. Further longitudinal studies are needed to explore the long-term effects of COVID-19 on brain structure.
Teresa Liu-Ambrose: The COVID-19 pandemic’s effects on cognition and 24-hour movement behaviours: Findings from the CLSA
Journal: Maturitas
This study examined the effects of the COVID-19 pandemic on cognition and movement behaviours in participants aged 45-85 years from the Canadian Longitudinal Study on Aging (CLSA). The analysis focused on cognitive performance and 24-hour movement behaviours (physical activity, sedentary behaviour, and sleep) before and during the pandemic. Results indicated that men aged 65-85 showed decreased animal fluency (ability to quickly generate a list of animals), reduced physical activity, and increased sedentary behaviour during the pandemic. Similarly, women in the same age group experienced decreased cognitive performance on the Mental Alternation Test and higher sedentary behaviour. However, no significant cognitive changes were observed in participants aged 45-64. Interestingly, changes in 24-hour movement behaviours were not linked to cognitive changes, suggesting that while the pandemic impacted movement behaviours differently by age and sex, these changes did not correlate with cognitive decline.
Helen Tremlett: Prodromal phase of multiple sclerosis: evidence from sickness absence patterns before disease onset – a matched cohort study
Journal: Journal of Neurology, Neurosurgery and Psychiatry
Research has shown that individuals in the prodromal phase of MS often experience increased healthcare utilization, such as more frequent physician visits and higher rates of hospitalizations. This study provides robust evidence of a significant increase in sickness absence rates in the years leading to MS onset. The increase in sickness absence may signal early health deterioration before the clinical onset of MS. These findings contribute to the growing body of knowledge on the prodromal phase of MS and the understanding of early disease impact. Investigating sick leave patterns may provide a unique and broad perspective on the health trajectories of chronic conditions like MS. Sickness absence data can be a valuable tool for gaining a deeper understanding of the early effects of MS on individuals’ lives, offering new avenues for research into the disease’s prodromal phase.
Read the blog post here.
